J. Mater. Sci. Technol. ›› 2025, Vol. 204: 292-301.DOI: 10.1016/j.jmst.2024.02.090

• Research Article • Previous Articles     Next Articles

A sol-gel strategy of constructing nanosized Hf6Ta2O17 encapsulated graphite flakes and its enhancement on the ablation property of carbon/carbon composites

Guanghui Fenga,b, Ruoxi Zhanga, Xiyuan Yaoa,*, Hejun Lia,*   

  1. aState Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials, Northwestern Polytechnical University, Xi'an 710072, China;
    bDepartment of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
  • Received:2023-08-22 Revised:2024-01-27 Accepted:2024-02-23 Published:2025-01-01 Online:2024-05-01
  • Contact: *E-mail addresses: yaoxiyuan@nwpu.edu.cn (X. Yao), lihejun@nwpu.edu.cn (H. Li).

Abstract: Herein, nanosized Hf6Ta2O17 encapsulated graphite flakes were firstly constructed using the sol-gel method, then deposited on the surface of carbon/carbon (C/C) composites by plasma spraying technique to prolong their service span in critical environments. Nanoindentation results affirmed the active influence of graphite flakes on elevating the toughness of the Hf6Ta2O17 coating. Besides, after being exposed to the oxyacetylene torch with a peak temperature of about 2000 °C, the sample achieved near zero ablation (0.06 mg/s), meanwhile its porosity and mass ablation rate showed 39.5 % and 60.0 % reduction when compared to pure Hf6Ta2O17 sample. During exposure, the external Hf6Ta2O17 served as an oxygen barrier for internal graphite flakes, inversely internal graphite flakes provided a “pinning” effect on external Hf6Ta2O17, which accounted for its exceptional ablation performance. This work offers a new insight into the design of surface modification of C/C composites and other high-temperature structural materials.

Key words: Carbon/carbon composites, Encapsulation structure, High-temperature properties, Thermal analysis